In a case that could wreck the 57-year-old’s hopes of a political comeback, Sarkozy is suspected of taking financial advantage of elderly L’Oreal heiress Liliane Bettencourt when she was too frail to fully understand what she was doing.

Sarkozy’s appearance comes with his right-wing UMP party in turmoil after the battle to replace him degenerated into mud-slinging and both contenders claiming victory.

Examining magistrate Jean-Michel Gentil and two other judges were expected to spend most of the day quizzing Sarkozy about how he obtained funding from Bettencourt.Judicial sources have told that Sarkozy could be formally indicted on a charge of taking advantage of someone in a position of weakness.

Bettencourt is now 90 and has been in poor health since 2006. The allegation against Sarkozy is two-fold: that the money obtained from her took his campaign financing over legal limits and that it had been secured without her full knowledge or consent.

This latter claim was made by Bettencourt’s former accountant, Claire Thibout, in 2010. She told police that she had handed 150,000 euros in cash to Bettencourt’s right-hand man, Patrice de Maistre, on the understanding it was to be passed on to Sarkozy’s campaign treasurer, Eric Woerth.